1. Field of the Invention
The present invention relates to a semiconductor device and a manufacturing method and an operating method thereof. More particularly, the present invention relates to a non-volatile memory and a manufacturing method and an operating method thereof.
2. Description of Related Art
Data can be written into and read or erased from an electrically erasable programmable read-only memory (EEPROM) repeatedly and the data stored in the EEPROM won't be lost even after the power is cut off. Thus, EEPRM among non-volatile memories has been broadly applied to personal computers and electronic equipments.
Typically, the floating gate and control gate of an EEPROM are fabricated with doped polysilicon, and the insulation layers between gates and the substrate and between gate and gate are silicon oxide layers.
However, a plurality of polysilicon layers and a plurality of silicon oxide layers are to be formed in the foregoing EEPROM. Thus, a plurality of mask processes has to be performed during the fabricating process, which not only prolongs the fabricating process but also increases the fabricating cost. Moreover, a memory cell in the EEPROM can only store a 1-bit data and the double-gate design also takes a lot of space, which are very disadvantageous to device integration.
Memories with nitride charge trapping layers have been provided later on. According to the memory cell structure, charges are trapped in a silicon nitride dielectric layer for storing data. Even though the memory with nitride charge trapping layer can store 2-bit data in a single memory cell, the 2 data bits may affect each other and which reduces the reliability of the memory. Moreover, it cannot provide good charge endurance. Hence, a non-volatile memory having high integration and high reliability is required.